Question

In a sequence of DNA taken from various species of snails, researchers have found that the rates of nonsynonymous substitutions and synonymous substitutions are roughly the same. What can we infer from this pattern?

a. Transversions are more common than transitions.
b. Most of the amino-acid changes are neutral.
c. Strong stabilizing selection is acting on this gene.
d. Strong selection for change is acting on this gene.
e. None of the above

Answer 1

The answer is D.

Step-by-step explanation:

Nonsynonymous substitutions refer to changes in DNA that affect the amino-acids whereas synonymous substitutions do not have any effect to amino-acid sequences.

From the information in the question that the synonymous and nonsynonymous substitution rates are about equal, we can infer that strong selection is acting on this gene because even though the rates are equal, amino-acid sequences are still getting effected by the changes and this results in a change or a mutation.

I hope this answer helps.